Added main.cpp file. It's functional. Files are compared by file size…

… only.

README.md

@@ -1,2 +1,22 @@
 # dubdog
 An ultimate CLI duplicate file finder and remover!
+
+This is a demo project to demonstrate my skills in C++11/14/17/20.
+I intentionally put all code into just one main.cpp file because it's simple to review it by page scrolling.
+
+While created as demo project it still could be really useful in to finding and removing duplicate files.
+
+Build it with 
+g++ main.cpp -o dubdog
+
+Usage:
+dubdog path extensions
+
+extensions - is comma separated list of file's extensions.
+
+For example when running on Windows you may run:
+dubdog 'C:\Books' pdf,djvu,epub,fb2
+
+Current version compares files only by file's size (not MD5 or similar message digest). 
+Thus we careful to use it on real files.
+

main.cpp

@@ -0,0 +1,107 @@
+#include <iostream>
+#include <cstdint>
+#include <thread>
+#include <filesystem>
+#include <vector>
+#include <map>
+#include <regex>
+#include <memory>
+#include <fstream>
+#include <cstring>
+#include <iomanip>
+
+using namespace std;
+
+
+class DupList
+{
+public:
+   uintmax_t fsize;
+   vector<string> lst;
+};
+
+int main(int argc, char *argv[])
+{
+   if (argc < 3) {
+      cout << "Usage: " << endl;
+      cout << "   dupdog path masks" << endl;
+      cout << "Example:" << endl;
+      cout << "   dupbog C:\\books pdf;djvu;epub;fb2" << endl;
+      return 0;
+   }
+   cout << "Scanning for duplicate files..." << endl;
+
+   string FilePath = argv[1];
+
+   char *exts = argv[2];
+   char *ext = strtok(exts, ",");
+   string masks = "";
+   while (ext) {
+      if (masks.size() > 0) masks += "|";
+      masks += "\\."+string(ext);
+      ext = strtok(nullptr, ",");
+   }
+
+   regex mask {"("+masks+")"};
+   string ExtMask;
+
+   map<uintmax_t,shared_ptr<DupList>> candidates;
+
+   using rdi = std::filesystem::recursive_directory_iterator;
+   for (const auto& entry : rdi(FilePath)) {
+      string ext = entry.path().extension().string();
+      if (entry.is_regular_file() && regex_match(ext, mask)) {
+         auto& dup = candidates[entry.file_size()];
+         if (dup == nullptr) {
+               shared_ptr<DupList> newdup(new DupList());
+               candidates[entry.file_size()] = newdup;
+               dup = candidates[entry.file_size()];
+         }
+         dup->fsize = entry.file_size();
+         dup->lst.push_back(entry.path().string());
+
+      }
+   }
+
+   cout << "Printing duplicates:" << endl;
+   int no = 1;
+   vector<string> flist;
+   for (const auto& [fsize, dup] : candidates) {
+      if (dup->lst.size() > 1) {
+         cout << "size: " << fsize << endl;
+         for (const auto& f : dup->lst) {
+            cout << "#" << no << " " << f << endl;
+            flist.push_back(f);
+            no++;
+         }
+      }
+   }
+   cout << "Which files do you want to remove? Write down files numbers separated by space and press Enter" << endl;
+   cout << "Or just press Enter if you don't want to remove any files." << endl;
+   string filenumbers;
+   cout << ">";
+   std::getline(std::cin, filenumbers);
+
+   if (filenumbers.size()>0) {
+      char *fn = new char[filenumbers.length() + 1];
+      strcpy(fn, filenumbers.c_str());
+      char *num;
+      num = strtok(fn," ");
+      int i;
+      while (num) {
+         i = stoi(num) ;
+         cout << "Removing file: #" << i << " " << flist[i-1] << endl;
+         try {
+            filesystem::remove(flist[i-1]);
+         }
+         catch (...) {
+            cout << "Cannot remove file" << endl;
+         }
+         num = strtok(nullptr," ");
+      }
+      delete [] fn;
+   }
+   cout << "Done!" << endl;
+
+   return 0;
+}